Maximum aerobic capacity (VO2 max) (Amount of O2 (mL) consumed by 1Kg of body weight per minute) in the horse is 2.6 times that in cattle and 2-2.5 times that in high trained man. One of the most physiological factor for the reasons that hemoglobin concentration in blood of horse is higher than the other animal like racing camel, so when you try to give hematonics to elevate the hemoglobin of horse the result will be promising but in camel can't tolerate the hematonic and lead to give negative result because camel cant adapted with high hemoglobin concentration.